Anti-VEGF antibody

ABSTRACT

An antibody is provided. In certain cases, the antibody comprises: a) a heavy chain variable domain that comprises CDR regions that are substantially identical to the heavy chain CDR regions of a selected antibody and b) a light chain variable domain that comprises CDR regions that are substantially identical to the light chain CDR regions of the selected antibody, where the antibody binds a selected target.

CROSS-REFERENCING

This application is a divisional of U.S. patent application Ser. No.12/247,933, filed on Oct. 8, 2008, and now U.S. Pat. No. 7,803,371,which application claims the benefit of U.S. provisional applicationSer. No. 61/039,719, filed on Mar. 26, 2008.

BACKGROUND

Antibodies are proteins that bind a specific antigen. Generally,antibodies are specific for their targets, have the ability to mediateimmune effector mechanisms, and have a long half-life in serum. Suchproperties make antibodies powerful therapeutics. Monoclonal antibodiesare used therapeutically for the treatment of a variety of conditionsincluding cancer, inflammation, and cardiovascular disease. There arecurrently over ten therapeutic antibody products on the market andhundreds in development.

There is a constant need for new antibodies.

SUMMARY OF THE INVENTION

An antibody is provided. In certain cases, the antibody comprises: a) aheavy chain variable domain that comprises CDR regions that aresubstantially identical to the heavy chain CDR regions of a selectedantibody shown in FIG. 1 and b) a light chain variable domain thatcomprises CDR regions that are substantially identical to the lightchain CDR regions of the selected antibody, where the antibody binds aselected target. In particular embodiments, the CDR regions of theantibody may collectively contain, for example, one, two, three, four,five or up to 10 amino acid differences (e.g., amino acid substitutions,deletions or insertions) relative to the CDR regions of the selectedantibody. In certain cases, the CDR regions of a subject antibody mayhave an amino acid sequence that is defined by a consensus sequencederived from analysis of several related antibodies. In some embodimentsthe CDR regions of the antibody may be identical to the CDR regions ofthe selected antibody.

In particular embodiments, the antibody may comprise: a variable domaincomprising: a) a heavy chain variable domain comprising: i. a CDR1region that is identical in amino acid sequence to the heavy chain CDR1region of a selected antibody of FIG. 1; ii. a CDR2 region that isidentical in amino acid sequence to the heavy chain CDR2 region of theselected antibody; and iii. a CDR3 region that is identical in aminoacid sequence to the heavy chain CDR3 region of the selected antibody;and b) a light chain variable domain comprising: i. a CDR1 region thatis identical in amino acid sequence to the light chain CDR1 region ofthe selected antibody; ii. a CDR2 region that is identical in amino acidsequence to the light chain CDR2 region of the selected antibody; andiii. a CDR3 region that is identical in amino acid sequence to the lightchain CDR3 region of the selected antibody; wherein the antibodyspecifically binds a selected target.

In certain embodiments, an antibody comprising: a) a variable domaincomprising: i. a CDR1 region that is identical in amino acid sequence tothe heavy chain CDR1 region of a selected antibody of FIG. 1; ii. a CDR2region that is identical in amino acid sequence to the heavy chain CDR2region of the selected antibody; and iii. a CDR3 region that isidentical in amino acid sequence to the heavy chain CDR3 region of theselected antibody; and b) a light chain variable domain comprising: i. aCDR1 region that is identical in amino acid sequence to the light chainCDR1 region of the selected antibody; ii. a CDR2 region that isidentical in amino acid sequence to the light chain CDR2 region of theselected antibody; and iii. a CDR3 region that is identical in aminoacid sequence to the light chain CDR3 region of the selected antibody;or b) a variant of the variable domain of part a) that is otherwiseidentical to the variable domain of part a) except for a number of(e.g., 1, 2, 3, 4, 5, 6, 7 or 8) amino acid substitutions in the CDRregions, where the antibody binds a selected target and, in certainembodiments, the activity of the selected target.

In certain embodiments, the antibody may comprise the CDRs of a CDRconsensus group selected from Table 1. In particular embodiments, theantibody may comprise: a) a heavy chain variable domain comprising: i. aCDR1 region comprising the CDR1 amino acid sequence of a CDR consensusgroup selected from Table 1; ii. a CDR2 region comprising the CDR2 aminoacid sequence of the selected CDR consensus sequence; and iii a CDR3region comprising the CDR3 amino acid sequence of the selected CDRconsensus sequence; and b) a light chain variable domain comprising: i.a CDR1 region comprising the CDR1 amino acid sequence of the selectedCDR consensus sequence; ii. a CDR2 region comprising the CDR2 amino acidsequence of the selected CDR consensus sequence; and iii a CDR3 regioncomprising the CDR3 amino acid sequence of the selected CDR consensussequence; wherein said antibody specifically binds a selected targetand, in certain embodiments, the activity of the selected target.

A pharmaceutical composition comprising a subject antibody and apharmaceutically acceptable carrier is also provided.

A method is also provided. In certain embodiments, the method maycomprise contacting a subject antibody with a target of the antibodyunder conditions suitable for binding of the antibody to the target toproduce a complex.

Also provided is a method of blocking binding of a ligand to itsreceptor. In certain embodiments, this method may comprise:administering a subject antibody to a subject, wherein said antibodybinds to either the receptor or the ligand in said subject and blocksbinding of said ligand and its receptor.

The selected target may be VEGF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the amino acid sequences of selected VEGF-blockingantibodies. Page 1 of FIG. 1 shows amino acid sequences of the heavychains. Page 2 of FIG. 1 shows amino acid sequences of the correspondinglight chains. The amino acid sequences of the CDRs of each antibody areboxed. The amino acid sequences shown in FIG. 1 are of antibodies thatspecifically bind to VEGF and neutralize VEGF activity. From top tobottom, FIG. 1 (page 1 of 2) SEQ ID NO: 1-38 and FIG. 1 (page 2 of 2)SEQ ID NO: 39-76.

DEFINITIONS

Before the present subject invention is described further, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. All publications mentioned herein areincorporated herein by reference to disclose and describe the methodsand/or materials in connection with which the publications are cited.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “and”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “anantibody” includes a plurality of such antibodies and reference to “aframework region” includes reference to one or more framework regionsand equivalents thereof known to those skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

The terms “antibody” and “immunoglobulin” are used interchangeablyherein. These terms are well understood by those in the field, and referto a protein consisting of one or more polypeptides that specificallybinds an antigen. One form of antibody constitutes the basic structuralunit of an antibody. This form is a tetramer and consists of twoidentical pairs of antibody chains, each pair having one light and oneheavy chain. In each pair, the light and heavy chain variable regionsare together responsible for binding to an antigen, and the constantregions are responsible for the antibody effector functions.

The recognized immunoglobulin polypeptides include the kappa and lambdalight chains and the alpha, gamma (IgG₁, IgG₂, IgG₃, IgG₄), delta,epsilon and mu heavy chains or equivalents in other species. Full-lengthimmunoglobulin “light chains” (of about 25 kDa or about 214 amino acids)comprise a variable region of about 110 amino acids at the NH₂-terminusand a kappa or lambda constant region at the COOH-terminus. Full-lengthimmunoglobulin “heavy chains” (of about 50 kDa or about 446 aminoacids), similarly comprise a variable region (of about 116 amino acids)and one of the aforementioned heavy chain constant regions, e.g., gamma(of about 330 amino acids).

The terms “antibodies” and “immunoglobulin” include antibodies orimmunoglobulins of any isotype, fragments of antibodies which retainspecific binding to antigen, including, but not limited to, Fab, Fv,scFv, and Fd fragments, chimeric antibodies, humanized antibodies,single-chain antibodies, and fusion proteins comprising anantigen-binding portion of an antibody and a non-antibody protein. Theantibodies may be detectably labeled, e.g., with a radioisotope, anenzyme which generates a detectable product, a fluorescent protein, andthe like. The antibodies may be further conjugated to other moieties,such as members of specific binding pairs, e.g., biotin (member ofbiotin-avidin specific binding pair), and the like. The antibodies mayalso be bound to a solid support, including, but not limited to,polystyrene plates or beads, and the like. Also encompassed by the termare Fab′, Fv, F(ab′)₂, and or other antibody fragments that retainspecific binding to antigen, and monoclonal antibodies. An antibody maybe monovalent or bivalent.

Antibodies may exist in a variety of other forms including, for example,Fv, Fab, and (Fab′)₂, as well as bi-functional (i.e. bi-specific) hybridantibodies (e.g., Lanzavecchia et al., Eur. J. Immunol. 17, 105 (1987))and in single chains (e.g., Huston et al., Proc. Natl. Acad. Sci.U.S.A., 85, 5879-5883 (1988) and Bird et al., Science, 242, 423-426(1988), which are incorporated herein by reference). (See, generally,Hood et al., “Immunology”, Benjamin, N.Y., 2nd ed. (1984), andHunkapiller and Hood, Nature, 323, 15-16 (1986).

An immunoglobulin light or heavy chain variable region consists of a“framework” region (FR) interrupted by three hypervariable regions, alsocalled “complementarity determining regions” or “CDRs”. The extent ofthe framework region and CDRs have been precisely defined (see,“Sequences of Proteins of Immunological Interest,” E. Kabat et al., U.S.Department of Health and Human Services, (1991)). The numbering of allantibody amino acid sequences discussed herein conforms to the Kabatsystem. The sequences of the framework regions of different light orheavy chains are relatively conserved within a species. The frameworkregion of an antibody, that is the combined framework regions of theconstituent light and heavy chains, serves to position and align theCDRs. The CDRs are primarily responsible for binding to an epitope of anantigen.

Chimeric antibodies are antibodies whose light and heavy chain geneshave been constructed, typically by genetic engineering, from antibodyvariable and constant region genes belonging to different species. Forexample, the variable segments of the genes from a non-human monoclonalantibody may be joined to human constant segments, such as gamma 1 andgamma 3. An example of a therapeutic chimeric antibody is a hybridprotein composed of the variable or antigen-binding domain from a rabbitantibody and the constant or effector domain from a human antibody(e.g., the anti-Tac chimeric antibody made by the cells of A.T.C.C.deposit Accession No. CRL 9688), although other mammalian species may beused.

As used herein, the term “humanized antibody” or “humanizedimmunoglobulin” refers to an non-human (e.g., mouse or rabbit) antibodycontaining one or more amino acids that have been substituted with acorrespondingly positioned amino acid from a human antibody. In somecases, humanized antibodies produce a reduced immune response in a humanhost, as compared to a non-humanized version of the same antibody.

It is understood that the humanized antibodies designed and produced bythe present method may have amino acid substitutions which havesubstantially no effect on antigen binding or other antibody functions.

“Similar amino acids” defined as follows: gly, ala; val, ile, leu; asp,glu; asn, gln; ser, thr; lys, arg; and phe, tyr. In other words, gly andala are similar amino acids; val, ile and leu are similar amino acids;asp and glu are similar amino acids; asn and gln are similar aminoacids; ser and thr are similar amino acids; lys and arg are similaramino acids; and phe and tyr are similar amino acids. Substituting anamino acid for a similar amino acid is termed a “conservative amino acidsubstitution” herein. Amino acids that are not present in the same groupas set forth above are “dis-similar” amino acids.

The term “specific binding” refers to the ability of an antibody topreferentially bind to a particular analyte that is present in ahomogeneous mixture of different analytes. In certain embodiments, aspecific binding interaction will discriminate between desirable andundesirable analytes in a sample, in some embodiments more than about 10to 100-fold or more (e.g., more than about 1000- or 10,000-fold).

In certain embodiments, the affinity between an antibody and its targetwhen they are specifically bound in a capture agent/analyte complex ischaracterized by a K_(D) (dissociation constant) of less than 10⁻⁶ M,less than 10⁻⁷ M, less than 10⁻⁸ M, less than 10⁻⁹ M, less than 10⁻⁹ M,less than 10⁻¹¹ M, or less than about 10⁻¹² M or less.

A “variable region” of a heavy or light antibody chain is an N-terminalmature domain of the chains. All domains, CDRs and residue numbers areassigned on the basis of sequence alignments and structural knowledge.Identification and numbering of framework and CDR residues is asdescribed in by Kabat, Chothia (Chothia, Structural determinants in thesequences of immunoglobulin variable domain. J Mol Biol 1998;278:457-79) and others.

VH is the variable domain of an antibody heavy chain. VL is the variabledomain of an antibody light chain, which could be of the kappa (K) or ofthe lambda isotype. K-1 antibodies have the kappa-1 isotype whereas K-2antibodies have the kappa-2 isotype and Vλ is the variable lambda lightchain.

As used herein, the terms “determining,” “measuring,” and “assessing,”and “assaying” are used interchangeably and include both quantitativeand qualitative determinations.

The terms “polypeptide” and “protein”, used interchangeably herein,refer to a polymeric form of amino acids of any length, which caninclude coded and non-coded amino acids, chemically or biochemicallymodified or derivatized amino acids, and polypeptides having modifiedpeptide backbones. The term includes fusion proteins, including, but notlimited to, fusion proteins with a heterologous amino acid sequence,fusions with heterologous and homologous leader sequences, with orwithout N-terminal methionine residues; immunologically tagged proteins;fusion proteins with detectable fusion partners, e.g., fusion proteinsincluding as a fusion partner a fluorescent protein, β-galactosidase,luciferase, etc.; and the like. Polypeptides may be of any size, and theterm “peptide” refers to polypeptides that are 8-50 residues (e.g., 8-20residues) in length.

As used herein the term “isolated,” when used in the context of anisolated antibody, refers to an antibody of interest that is at least60% free, at least 75% free, at least 90% free, at least 95% free, atleast 98% free, and even at least 99% free from other components withwhich the antibody is associated with prior to purification.

The terms “treatment” “treating” and the like are used herein to referto any treatment of any disease or condition in a mammal, e.g.particularly a human or a mouse, and includes: a) preventing a disease,condition, or symptom of a disease or condition from occurring in asubject which may be predisposed to the disease but has not yet beendiagnosed as having it; b) inhibiting a disease, condition, or symptomof a disease or condition, e.g., arresting its development and/ordelaying its onset or manifestation in the patient; and/or c) relievinga disease, condition, or symptom of a disease or condition, e.g.,causing regression of the condition or disease and/or its symptoms.

The terms “subject,” “host,” “patient,” and “individual” are usedinterchangeably herein to refer to any mammalian subject for whomdiagnosis or therapy is desired, particularly humans. Other subjects mayinclude cattle, dogs, cats, guinea pigs, rabbits, rats, mice, horses,and so on.

“Corresponding amino acids”, are amino acid residues that are at anidentical position (i.e., they lie across from each other) when two ormore amino acid sequences are aligned. Methods for aligning andnumbering antibody sequences are set forth in great detail in Kabatsupra, and others. As is known in the art (see, e.g. Kabat 1991Sequences of Proteins of Immunological Interest, DHHS, Washington,D.C.), sometimes one, two or three gaps and/or insertions of up to one,two, three or four residues, or up to about 15 residues (particularly inthe L3 and H3 CDRs) may be made to one or both of the amino acids of anantibody in order to accomplish an alignment.

A “natural” antibody is an antibody in which the heavy and lightimmunoglobulins of the antibody have been naturally selected by theimmune system of a multi-cellular organism, as opposed to unnaturallypaired antibodies made by e.g. phage display, or humanized antibodies.As such, certain antibodies do not contain any viral (e.g.,bacteriophage M13)-derived sequences. Spleen, lymph nodes and bonemarrow are examples of tissues that produce natural antibodies.

A “parent” antibody is an antibody is the target of amino acidsubstitutions. In certain embodiments, amino acids may be “donated” by a“donor” antibody to the parent antibody to produce an altered antibody.

“Related antibodies” are antibodies that have a similar sequence andproduced by cells that have a common B cell ancestor. Such a B cellancestor contains a genome having a rearranged light chain VJC regionand a rearranged heavy chain VDJC region, and produces an antibody thathas not yet undergone affinity maturation. “Naïve” or “virgin” B cellspresent in spleen tissue, are exemplary B cell common ancestors. Relatedantibodies bind to the same epitope of an antigen and are typically verysimilar in sequence, particularly in their L3 and H3 CDRs. Both the H3and L3 CDRs of related antibodies have an identical length and a nearidentical sequence (e.g., differ by 0-4 residues). Related antibodiesare related via a common antibody ancestor, the antibody produced in thenaïve B cell ancestor. The term “related antibodies” is not intended todescribe a group of antibodies that do not have a common antibodyancestor produced by a B-cell. In certain cases, related antibodies: i.bind to the same antigen; ii. each comprise heavy chain variable domainsthat have an overall amino acid sequence identity of at least 90%relative to one another; iii. each comprise light chain variable domainsthat have an overall amino acid sequence identity of at least 90%relative to one another; iv. have H3 CDRs that are identical in lengthand identical in sequence except for 0, 1 or 2 amino acid substitutionsrelative to one another; and v. have L3 CDRs that are identical inlength and identical in sequence except for 0, 1 or 2 amino acidsubstitutions relative to one another;

A “blocking antibody”, “neutralizing antibody” or “antibody thatneutralizes” or any grammatical equivalent thereof refers to an antibodywhose binding to a target results in inhibition binding to a target orof a biological activity of the target e.g., by at least about 20%, 30%,40%, 50%, 80%, 95% or 99%. This inhibition of the biological activity ofa target can be assessed by measuring one or more indicators of thetarget's biological activity, such as activation of a signaltransduction pathway, binding, or cellular changes effected by thetarget. The biological activity of the targets described herein can beassessed by one or more of several standard in vitro or in vivo assaysknown in the art.

The term “VEGF” or its non-abbreviated form “vascular endothelial growthfactor”, as used herein, refers the protein products encoded by the VEGFgene. VEGF is involved in both vasculogenesis (the de novo formation ofthe embryonic circulatory system) and angiogenesis (the growth of bloodvessels from pre-existing vasculature). All members of the VEGF familystimulate cellular responses by binding to tyrosine kinase receptors(the VEGFRs) on the cell surface, causing them to dimerize and becomeactivated through transphosphorylation. The VEGF receptors have anextracellular portion containing 7 immunoglobulin-like domains, a singletransmembrane spanning region and an intracellular portion containing asplit tyrosine-kinase domain. VEGF-A binds to VEGFR-1 (Flt-1) andVEGFR-2 (KDR/Flk-1). VEGFR-2 appears to mediate almost all of the knowncellular responses to VEGF. VEGF, its biological activities, and itsreceptors are well studied and are described in Matsumoto et al (VEGFreceptor signal transduction Sci STKE. 2001:RE21 and Marti et al(Angiogenesis in ischemic disease. Thromb Haemost. 1999 Suppl 1:44-52).The term VEGF is intended to include recombinant VEGF molecules, whichcan be prepared by standard recombinant expression methods or purchasedcommercially (R & D Systems, Catalog No. 210-TA, Minneapolis, Minn.), aswell as fusion proteins containing a VEGF molecule. Amino acid sequencesof exemplary VEGFs that may be employed herein are found in the NCBI'sGenbank database and a full description of human VEGF and its role invarious diseases and conditions is found in NCBI's Online MendelianInheritance in Man database.

DETAILED DESCRIPTION

An antibody is provided. In certain cases, the antibody comprises: a) aheavy chain variable domain that comprises CDR regions that aresubstantially identical to the heavy chain CDR regions of a selectedantibody shown in FIG. 1 and b) a light chain variable domain thatcomprises CDR regions that are substantially identical to the lightchain CDR regions of the selected antibody, where the antibody binds aselected target. In particular embodiments, the CDR regions of theantibody may collectively contain, for example, one, two, three, four,five up to 10 amino acid differences (e.g., amino acid substitutions,deletions or insertions) relative to the CDR regions of the selectedantibody. In some embodiments the CDR regions of the antibody may beidentical to the CDR regions of the selected antibody. As would bereadily apparent, such an antibody further contains framework sequencesthat position the CDRs.

In particular embodiments, a subject antibody may have: a) a heavy chainvariable domain having an amino acid sequence that is at least 80%identical (e.g., at least 90%, at least 95% or at least 98% or 99%identical) to the heavy chain variable domain of a selected antibodyshown in FIG. 1 and b) a light chain variable domain having an aminoacid sequence that is at least 80% identical (e.g., at least 90%, atleast 95% or at least 98% or 99% identical) to the light chain variabledomain of the selected antibody.

In particular embodiments, the antibody may comprise: a) a heavy chainvariable domain comprising: i. a CDR1 region that is identical in aminoacid sequence to the heavy chain CDR1 region of a selected antibody ofFIG. 1; ii. a CDR2 region that is identical in amino acid sequence tothe heavy chain CDR2 region of the selected antibody; and iii. a CDR3region that is identical in amino acid sequence to the heavy chain CDR3region of the selected antibody; and b) a light chain variable domaincomprising: i. a CDR1 region that is identical in amino acid sequence tothe light chain CDR1 region of the selected antibody; ii. a CDR2 regionthat is identical in amino acid sequence to the light chain CDR2 regionof the selected antibody; and iii. a CDR3 region that is identical inamino acid sequence to the light chain CDR3 region of the selectedantibody; wherein the antibody specifically binds a selected target.

Immunization of a rabbit with a single antigen yields multipleantibodies that can be grouped by the relatedness of their sequence. Theantibodies within each group are related to each other in that they areproduced by cells that have a common naïve B cell ancestor. The antibodyproduced by the ancestral B cell does has not yet undergone affinitymaturation, whereas the related antibodies have undergone affinitymaturation and the final stage of B-cell development and have “evolved”from the common B-cell ancestor antibody in that they contain amino acidsubstitutions caused by somatic hypermutation, gene conversion and othercellular mutation events that occur during affinity maturation.

The amino acid sequence of related antibodies can be compared (e.g., byaligning those sequences), and the antibodies are classified accordingto their similarity to each other to identify related groups ofantibodies. The antibodies of a group of related antibodies generallycontain a near identical sequence, have CDR regions that are identicalin length, and have differences in amino acid sequence in the frameworkand/or CDR regions. These differences indicate amino acids that can besubstituted in either of the related antibodies. In certain cases, theamino acids at a position may be dis-similar amino acids, in which casean amino acid at that position may be substituted with any other aminoacid, for example. In other cases, the amino acids at a position may besimilar amino acids, in which case an amino acid at that position may besubstituted with a similar amino acid, where a similar amino acid isdefined above. In certain cases, the amino acid may be substituted fromone related antibody to another, if the amino acid is different.

Since each of the CDRs of a particular consensus group were originallyproduced and effectively tested by the immune system of the immunizedanimal, substituting one amino acid for another consensus amino acidshould be well tolerated by the antibody. The antibodies of FIG. 1 werealigned, groups of related antibodies were identified, and consensussequences were identified. In certain cases, an antibody may comprisethe CDRs of a CDR consensus group, where the CDR consensus groups arederived from sequence alignments of related antibodies. The consensussequences of the antibodies of FIG. 1 are shown in Table 1. Table 1indicates substitutable positions in a subject antibody, where asubstitution may be to any other amino acid, a similar amino acid (i.e.,a conservative amino acid substitution), or from one antibody toanother, for example. Such methods are further described in U.S. patentapplication Ser. No. 10/984,473 (published as US-2006-0099204), which isincorporated by reference for disclosure of those methods.

In certain embodiments, the antibody may comprise the CDRs of a CDRconsensus group selected from Table 1. In particular embodiments, theantibody may comprise: a) a heavy chain variable domain comprising: i. aCDR1 region comprising the CDR1 amino acid sequence of a CDR consensusgroup selected from Table 1; ii. a CDR2 region comprising the CDR2 aminoacid sequence of the selected CDR consensus sequence; and iii a CDR3region comprising the CDR3 amino acid sequence of the selected CDRconsensus sequence; and b) a light chain variable domain comprising: i.a CDR1 region comprising the CDR1 amino acid sequence of the selectedCDR consensus sequence; ii. a CDR2 region comprising the CDR2 amino acidsequence of the selected CDR consensus sequence; and iii a CDR3 regioncomprising the CDR3 amino acid sequence of the selected CDR consensussequence; wherein said antibody specifically binds a selected target.

For example, such an antibody may comprise: a) a heavy chain variabledomain having: i. a CDR1 of the formula: NNA/DVMC (SEQ ID NO:77), a CDR2of the formula: CIMTTDVVTE/AYANWAKS (SEQ ID NO:78), and a CDR3 of theformula: DSVGSPLMSFDL (SEQ ID NO:79), and; b) a light chain variabledomain having: a CDR1 of the formula: QASQN/SL/VYN/GNNELS (SEQ IDNO:80), a CDR2 of the formula: W/RASTLAS (SEQ ID NO:81) and a CDR3 ofthe formula: A/S/GGYKSYS/YND/GGN/SG (SEQ ID NO:82), where the antibodyblocks VEGF.

TABLE 1 CDR SEQ SEQ SEQ Consensus ID ID ID groups Activity AntibodyCDR 1 NO. CDR 2 NO. CDR 3 NO. HEAVY CHAIN I VEGF  2, 7, 20,  NNA/DVMC 77CIMTTDVVTE/AYANWAKS 78 DSVGSPLMSFDL 79 binding 21, 23 II VEGF  1, 4, 8SS/N/GYY/DMC 83 CIYTGSN/GN/RTY/HYAY/ 84 A/GI/NSINVYV/A/GL/V  85 bindingSWG/AKG III VEGF  3, 13 SSYNM/IC 89 CIHGGD/SDGTTYYATWAKG 90 DEWAGTRLK/NL91 binding IV VEGF  R1, R19,  T/S/I/VYEG/MS/N 95Y/VIYT/P/SDS/GD/STVYAT/  96 G/TDLS/NS/TGWGAA/N/DL 97 binding R13, R33SWAKG V VEGF  R2, R4,  NYYWN 101 FIDLLGSADYASWAKG 102 SGSH/SSGWG/CADI103 binding R9, R14 VI VEGF  R10, R31 SYYMN 107 FID FS/GSDAYYANWAKG 108SGVDSA/GWGFDL 109 binding VII VEGF  R7, R16,  SYDM/II 113YIDA/TV/IGSST/RYYASWAKG 114 GDWSTAWGFNL 115 binding R18 VIII VEGF R8, R15, SYAV/MS 119 IIS/TSSG/VS/ITYYASWAKG 120 DAN/SSR/TGYYIPYYFNI 121binding R30 IX VEGF  R23, R24 SYAMG 125 IIYLETGNTYYATWAKG 126 GSWSDYAL127 binding LIGHT CHAIN I VEGF  2, 7, 20,  QASQN/SL/VYN/ 80 W/RASTLAS 81A/S/GGYKSYS/YND/GGN/SG 82 binding 21, 23 GNNELS II VEGF  1, 4, 8QASQSID/GN/SSLT/ 86 R/GAST/NLE/AS 87 QGYYW/YG/SS/DT/A/SAD/  88 binding AENA III VEGF  3, 13 QASET/SINT/SF/ 92 QASTLAS 93 QSYFYG/KSGN/SYGFV/I 94binding WLS IV VEGF  R-1, R19,  QASEN/SIR/SS/ 98 QASK/S/RLAS 99QNC/SYS/RFST/A/S/IYGA/  100 binding R13, R33 NWLA GA V VEGF  R2, R4, QASQSIN/ST/ 104 QASKLAS 105 QNNYLMATYGGP 106 binding R9, R14 SWLS VIVEGF  R10, R31 QASQSIRSWLA 110 EASKLAF 111 QNS/DYGWTSYGAT 112 bindingVII VEGF  R7, R16,  QASQSISGWLS 116 QASKLAS 117 QSVYLI/VSTYGAT 118binding R18 VIII VEGF  R8, R15,  QASESIYSNLA 122 AAS/FYLAS 123QSAH/NYSSSGDIA 124 binding R30 IX VEGF  R23, R24 QSSQNVYSNDLLS 128EASKLAS 129 AGAYSGNINV 130 binding

In a particular embodiment, the antibody may comprise: a) a heavy chainvariable domain comprising CDRs comprising an amino acid sequence of theformulae: CDR1: (S/N)(N/S/−) YXM(C/N/S/I); CDR2:(C/F/Y/I)I(M/Y/D/S)(T/−)(G/−)XXXX(T/A)(Y/E/D/V) YA(N/S/T)WAK(G/S) (SEQID NO:131); CDR3: (G/D/S)(S/D/G/A)XXXX(L/W/Y/−)(X/−)(X/−)(X/−)(X/−)(Y/G/S/−)(F/A/Y/−)(A/N/D)(L/I), and; b) a light chain variabledomain comprising CDRs comprising an amino acid sequence of theformulae: CDR1:Q(A/S)S(E/Q)(S/N)(L/V/I)X(S/N/G/−)(N/D/−)(N/T/S/D/G)XL(S/T/A); CRD2:XAS(T/K/Y)L(A/E)S (SEQ ID NO:132); CDR3: (A/Q)(G/N/S)X(Y/K)XXXX(X/−)(G/D/−)(X/−) (X/−)X(G/T/A/P/V), wherein X is any amino acid, − denotesno residue, / denotes alternative amino acid present at a position, and( ) denotes one amino acid position. This antibody blocks VEGF.

Modified Antibodies

The above-described antibodies may modified by substituting, adding, ordeleting at least one amino acid. In one embodiment, an above-describedthe amino acid sequence of a subject antibody is modified to provide ahumanized antibody for human therapeutic use, or another type ofmodified antibody. In general, these modified antibodies have thegeneral characteristics of the above-described rabbit antibodies andcontain at least the CDRs of an above-described rabbit antibody, or, incertain embodiments, CDRs that are very similar to the CDRs of anabove-described rabbit antibody.

Humanized Antibodies

In one embodiment, therefore, the invention provides humanized versionsof the above-described antibodies. In general, humanized antibodies aremade by substituting amino acids in the framework regions of a parentnon-human antibody to produce a modified antibody that is lessimmunogenic in a human than the parent non-human antibody. Antibodiescan be humanized using a variety of techniques known in the artincluding, for example, CDR-grafting (EP 239,400; PCT publication WO91/09967; U.S. Pat. Nos. 5,225,539; 5,530,101; and 5,585,089), veneeringor resurfacing (EP 592,106; EP 519,596; Padlan, Molecular Immunology28(4/5):489-498 (1991); Studnicka et al., Protein Engineering7(6):805-814 (1994); Roguska. et al., PNAS 91:969-973 (1994)), and chainshuffling (U.S. Pat. No. 5,565,332). In certain embodiments, frameworksubstitutions are identified by modeling of the interactions of the CDRand framework residues to identify framework residues important forantigen binding and sequence comparison to identify unusual frameworkresidues at particular positions (see, e.g., U.S. Pat. No. 5,585,089;Riechmann et al., Nature 332:323 (1988)). Additional methods forhumanizing antibodies contemplated for use in the present invention aredescribed in U.S. Pat. Nos. 5,750,078; 5,502,167; 5,705,154; 5,770,403;5,698,417; 5,693,493; 5,558,864; 4,935,496; and 4,816,567, and PCTpublications WO 98/45331 and WO 98/45332. In particular embodiments, asubject rabbit antibody may be humanized according to the methods setforth in published U.S. patent applications 20040086979 and 20050033031.Accordingly, the antibodies described above may be humanized usingmethods that are well known in the art.

In one embodiment of particular interest, a subject antibody may behumanized in accordance with the methods set forth in great detail inU.S. patent application Ser. No. 10/984,473, filed on Nov. 8, 2004 andentitled “Methods for antibody engineering”, which application isincorporated by reference in its entirety. In general, this humanizationmethod involves identifying a substitutable position of an antibody bycomparing sequences of antibodies that bind to the same antigen, andreplacing the amino acid at that position with a different amino acidthat is present at the same position of a similar human antibody. Inthese methods, the amino acid sequence of a parental rabbit antibody iscompared to (i.e., aligned with) the amino acid sequences of otherrelated rabbit antibodies to identify variation tolerant positions. Theamino acid sequence of the variable domain of the parental rabbitantibody is usually compared to a database of human antibody sequences,and a human antibody that has an amino acid sequence that is similar tothat of the parental antibody is selected. The amino acid sequences ofthe parental antibody and the human antibody are compared (e.g.,aligned), and amino acids at one or more of the variation tolerantpositions of the parental antibody are substituted by correspondinglypositioned amino acids in the human antibody. In this humanizationmethod, the CDR regions of the antibody may be humanized in addition tothe framework regions.

The above-discussed variation tolerant position substitution methods arereadily incorporated into any known humanization method and are alsoreadily employed to produce humanized antibodies containing CDR regionsthat are altered with respect to the CDR regions of the parent antibody.Accordingly humanized antibodies containing altered versions of the CDRsof the above-described antibodies are provided.

As noted above, the subject antibody may be modified to provide amodified antibody. In particular embodiments, this method include makingone or more amino acid substitutions (e.g., one, up to two, up to three,up to four or up to five of more, usually up to 10 or more). An aminoacid substitution may be at any position, and the amino acid at thatposition may be substituted by an amino acid of any identity. In certainembodiments, a modified antibody may have the same generalcharacteristics of the above-described rabbit antibodies. In oneembodiment, after a substitutable position has been identified using themethods of U.S. Ser. No. 10/984,473, the amino acids at that positionmay be substituted. In particular embodiments, an amino acidsubstitution may be a humanizing substitution (i.e., a substitution thatmake the amino acid sequence more similar to that of a human antibody),a directed substitution (e.g., a substitution that make the amino acidsequence of an antibody more similar to that of a related antibody inthe same group), a random substitution (e.g., a substitution with any ofthe 20 naturally-occurring amino acids) or a conservative substitution(e.g., a substitution with an amino acid having biochemical propertiessimilar to that being substituted).

In certain embodiments, modified antibodies of the invention may containa heavy or light chain that is encoded by a polynucleotide thathybridizes under high stringency conditions to a rabbit heavy or lightchain-encoding nucleic acid. High stringency conditions includeincubation at 50° C. or higher in 0.1×SSC (15 mM saline/0.15 mM sodiumcitrate).

In certain embodiments, modified antibodies of the invention may containa heavy or light chain that is encoded by a polynucleotide that is atleast 80% identical to (e.g., at least 85%, at least 90%, at least 95%,at least 98%) a rabbit heavy or light chain-encoding nucleic acid. Thepercentage identity is based on the shorter of the sequences compared.Well known programs such as BLASTN (2.0.8) (Altschul et al. (1997) Nucl.Acids. Res. 25:3389-3402) using default parameters and no filter may beemployed to make a sequence comparison.

Methods of Use

The above-described antibodies may be employed in a variety of methods.One such method comprises: contacting a subject antibody with a targetof the antibody under conditions suitable for binding of the antibody tothe target to produce a complex. Such a method may be performed by ELISAor western blotting, or by any one of many immunological detectionmethods known in the art, for example. In other embodiments, a method ofblocking binding of a ligand to its receptor is provided. In theseembodiments, the method comprises: administering a subject antibody to asubject, where the antibody binds to either the receptor or the ligandin said subject and blocks binding thereof.

A subject antibody inhibits at least one activity of its target in therange of about 20% to 100%, e.g., by at least about 10%, at least about20%, at least about 30%, at least about 40%, at least about 50%, atleast about 60%, usually up to about 70%, up to about 80%, up to about90% or more. In certain assays, a subject antibody may inhibits itstarget with an IC₅₀ of 1×10⁻⁷ M or less (e.g., 1×10⁻⁷ M or less, 1×10⁻⁸M or less, 1×10⁻⁹ M or less, usually to 1×10⁻¹² M or 1×10⁻¹³ M). Inassays in which a mouse is employed, a subject antibody may have an ED₅₀of less then 1 μg/mouse (e.g., 10 ng/mouse to about 1 μg/mouse).

The protocols that may be employed in these methods are numerous, andinclude but are not limited to cell-free assays, e.g., binding assays;cellular assays in which a cellular phenotype is measured, e.g., geneexpression assays; and in vivo assays that involve a particular animal(which, in certain embodiments may be an animal model for a conditionrelated to the target). In certain cases, the assay may be avascularization assay.

In certain embodiments, a subject antibody may be contacted with a cellin the presence of VEGF, and a VEGF response phenotype of the cellmonitored.

Exemplary VEGF assays include assays using isolated protein in a cellfree systems, in vitro using cultured cells or in vivo assays. ExemplaryVEGF assays include, but are not limited to a receptor tyrosine kinaseinhibition assay (see, e.g., Cancer Research Jun. 15, 2006;66:6025-6032), an in vitro HUVEC proliferation assay (FASEB Journal2006; 20: 2027-2035), an in vivo solid tumor disease assay (U.S. Pat.No. 6,811,779) and an in vivo angiogenesis assay (FASEB Journal 2006;20: 2027-2035). These assays are well known in the art. The descriptionsof these assays are hereby incorporated by reference.

Exemplary TNF-α assays include in vitro assays using cell free systemsor using cultured cells or in vivo assays. As such, TNF-α assays includein vitro human whole blood assay and cell mediated cytotoxicity assay(U.S. Pat. No. 6,090,382), in vitro tumor human killing assay (see,e.g., published U.S. patent application 20040185047), in vivo tumorregression assay (USP Application 20040002589). Additional TNF-α assaysare described in a variety of publications, including 20040151722,20050037008, 20040185047, 20040138427, 20030187231, 20030199679, andBalazovich (Blood 1996 88: 690-696).

Methods for Producing Antibodies

In many embodiments, the nucleic acids encoding a subject monoclonalantibody are introduced directly into a host cell, and the cellincubated under conditions sufficient to induce expression of theencoded antibody. The antibodies of this invention are prepared usingstandard techniques well known to those of skill in the art incombination with the polypeptide and nucleic acid sequences providedherein. The polypeptide sequences may be used to determine appropriatenucleic acid sequences encoding the particular antibody disclosedthereby. The nucleic acid sequence may be optimized to reflectparticular codon “preferences” for various expression systems accordingto standard methods well known to those of skill in the art.

Any cell suitable for expression of expression cassettes may be used asa host cell. For example, yeast, insect, plant, etc., cells. In manyembodiments, a mammalian host cell line that does not ordinarily produceantibodies is used, examples of which are as follows: monkey kidneycells (COS cells), monkey kidney CVI cells transformed by SV40 (COS-7,ATCC CRL 165 1); human embryonic kidney cells (HEK-293, Graham et al. J.Gen Virol. 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10);chinese hamster ovary-cells (CHO, Urlaub and Chasin, Proc. Natl. Acad.Sci. (USA) 77:4216, (1980); mouse sertoli cells (TM4, Mather, Biol.Reprod. 23:243-251 (1980)); monkey kidney cells (CVI ATCC CCL 70);african green monkey kidney cells (VERO-76, ATCC CRL-1587); humancervical carcinoma cells (HELA, ATCC CCL 2); canine kidney cells (MDCK,ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); humanlung cells (W138, ATCC CCL 75); human liver cells (hep G2, HB 8065);mouse mammary tumor (MMT 060562, ATCC CCL 51); TRI cells (Mather et al.,Annals N.Y. Acad. Sci 383:44-68 (1982)); NIH/3T3 cells (ATCC CRL-1658);and mouse L cells (ATCC CCL-1). Additional cell lines will becomeapparent to those of ordinary skill in the art. A wide variety of celllines are available from the American Type Culture Collection, 10801University Boulevard, Manassas, Va. 20110-2209.

Methods of introducing nucleic acids into cells are well known in theart. Suitable methods include electroporation, particle gun technology,calcium phosphate precipitation, direct microinjection, and the like.The choice of method is generally dependent on the type of cell beingtransformed and the circumstances under which the transformation istaking place (i.e. in vitro, ex vivo, or in vivo). A general discussionof these methods can be found in Ausubel, et al, Short Protocols inMolecular Biology, 3rd ed., Wiley & Sons, 1995. In some embodimentslipofectamine and calcium mediated gene transfer technologies are used.

After the subject nucleic acids have been introduced into a cell, thecell is typically incubated, normally at 37° C., sometimes underselection, for a period of about 1-24 hours in order to allow for theexpression of the antibody. In most embodiment, the antibody istypically secreted into the supernatant of the media in which the cellis growing in.

In mammalian host cells, a number of viral-based expression systems maybe utilized to express a subject antibody. In cases where an adenovirusis used as an expression vector, the antibody coding sequence ofinterest may be ligated to an adenovirus transcription/translationcontrol complex, e.g., the late promoter and tripartite leader sequence.This chimeric gene may then be inserted in the adenovirus genome by invitro or in vivo recombination. Insertion in a non-essential region ofthe viral genome (e.g., region E1 or E3) will result in a recombinantvirus that is viable and capable of expressing the antibody molecule ininfected hosts. (e.g., see Logan & Shenk, Proc. Natl. Acad. Sci. USA81:355-359 (1984)). The efficiency of expression may be enhanced by theinclusion of appropriate transcription enhancer elements, transcriptionterminators, etc. (see Bittner et al., Methods in Enzymol. 153:51-544(1987)).

For long-term, high-yield production of recombinant antibodies, stableexpression may be used. For example, cell lines, which stably expressthe antibody molecule, may be engineered. Rather than using expressionvectors which contain viral origins of replication, host cells can betransformed with immunoglobulin expression cassettes and a selectablemarker. Following the introduction of the foreign DNA, engineered cellsmay be allowed to grow for 1-2 days in an enriched media, and then areswitched to a selective media. The selectable marker in the recombinantplasmid confers resistance to the selection and allows cells to stablyintegrate the plasmid into a chromosome and grow to form foci which inturn can be cloned and expanded into cell lines. Such engineered celllines may be particularly useful in screening and evaluation ofcompounds that interact directly or indirectly with the antibodymolecule.

Once an antibody molecule of the invention has been produced, it may bepurified by any method known in the art for purification of animmunoglobulin molecule, for example, by chromatography (e.g., ionexchange, affinity, particularly by affinity for the specific antigenafter Protein A, and sizing column chromatography), centrifugation,differential solubility, or by any other standard technique for thepurification of proteins. In many embodiments, antibodies are secretedfrom the cell into culture medium and harvested from the culture medium.

Formulations and Administration

The antibodies of the invention may be administered in any manner whichis medically acceptable. This may include injections, by parenteralroutes such as intravenous, intravascular, intraarterial, subcutaneous,intramuscular, intratumor, intraperitoneal, intraventricular,intraepidural, or others as well as oral, nasal, ophthalmic, rectal, ortopical. Sustained release administration is also specifically includedin the invention, by such means as depot injections or erodibleimplants. Localized delivery is particularly contemplated, by such meansas delivery via a catheter to one or more arteries, such as the renalartery or a vessel supplying a localized tumor.

The subject antibodies may be formulated with a pharmaceuticallyacceptable carrier. The term “pharmaceutically acceptable carrier” meansone or more organic or inorganic ingredients, natural or synthetic, withwhich the antibody is combined to facilitate its application. A suitablecarrier includes sterile saline although other aqueous and non-aqueousisotonic sterile solutions and sterile suspensions known to bepharmaceutically acceptable are known to those of ordinary skill in theart. An “effective amount” refers to that amount which is capable ofameliorating or delaying progression of the diseased, degenerative ordamaged condition. An effective amount can be determined on anindividual basis and will be based, in part, on consideration of thesymptoms to be treated and results sought. An effective amount can bedetermined by one of ordinary skill in the art employing such factorsand using no more than routine experimentation.

In one embodiment a subject antibody is administered to a patient byintravenous, intramuscular or subcutaneous injection. An antibody may beadministered within a dose range between about 0.1 mg/kg to about 100mg/kg; between about 1 mg/kg to 75 mg/kg; or about 10 mg/kg to 50 mg/kg.The antibody may be administered, for example, by bolus injunction or byslow infusion. Slow infusion over a period of 30 minutes to 2 hours maybe used.

Utility

A subject antibody is useful for treating a disorder relating to itstarget.

In one embodiment, the invention provides a method of treating a subjectfor a VEGF-related condition. The method generally involvesadministering a subject antibody to a subject having a VEGF-relateddisorder in an amount effective to treat at least one symptom of theVEGF-related disorder. VEGF-related conditions are generallycharacterized by excessive vascular endothelial cell proliferation,vascular permeability, edema or inflammation such as brain edemaassociated with injury, stroke or tumor; edema associated withinflammatory disorders such as psoriasis or arthritis, includingrheumatoid arthritis; asthma; generalized edema associated with burns;ascites and pleural effusion associated with tumors, inflammation ortrauma; chronic airway inflammation; capillary leak syndrome; sepsis;kidney disease associated with increased leakage of protein; and eyedisorders such as age related macular degeneration and diabeticretinopathy. Such conditions include breast, lung, colorectal and renalcancer.

Kits

Also provided by the subject invention are kits for practicing thesubject methods, as described above. The subject kits at least includeone or more of: a subject antibody, a nucleic acid encoding the same, ora cell containing the same. The subject antibody may be humanized. Otheroptional components of the kit include: buffers, etc., for administeringthe antibody or for performing an activity assay. The nucleic acids ofthe kit may also have restrictions sites, multiple cloning sites, primersites, etc to facilitate their ligation to non-rabbit antibody nucleicacids. The various components of the kit may be present in separatecontainers or certain compatible components may be precombined into asingle container, as desired.

In addition to above-mentioned components, the subject kits typicallyfurther include instructions for using the components of the kit topractice the subject methods. The instructions for practicing thesubject methods are generally recorded on a suitable recording medium.For example, the instructions may be printed on a substrate, such aspaper or plastic, etc. As such, the instructions may be present in thekits as a package insert, in the labeling of the container of the kit orcomponents thereof (i.e., associated with the packaging or subpackaging)etc. In other embodiments, the instructions are present as an electronicstorage data file present on a suitable computer readable storagemedium, e.g. CD-ROM, diskette, etc. In yet other embodiments, the actualinstructions are not present in the kit, but means for obtaining theinstructions from a remote source, e.g. via the internet, are provided.An example of this embodiment is a kit that includes a web address wherethe instructions can be viewed and/or from which the instructions can bedownloaded. As with the instructions, this means for obtaining theinstructions is recorded on a suitable substrate.

Also provided by the subject invention are kits including at least acomputer readable medium including programming as discussed above andinstructions. The instructions may include installation or setupdirections. The instructions may include directions for use of theinvention with options or combinations of options as described above. Incertain embodiments, the instructions include both types of information.

Providing the software and instructions as a kit may serve a number ofpurposes. The combination may be packaged and purchased as a means forproducing rabbit antibodies that are less immunogenic in a non-rabbithost than a parent antibody, or nucleotide sequences thereof.

The instructions are generally recorded on a suitable recording medium.For example, the instructions may be printed on a substrate, such aspaper or plastic, etc. As such, the instructions may be present in thekits as a package insert, in the labeling of the container of the kit orcomponents thereof (i.e., associated with the packaging orsubpackaging), etc. In other embodiments, the instructions are presentas an electronic storage data file present on a suitable computerreadable storage medium, e.g., CD-ROM, diskette, etc, including the samemedium on which the program is presented.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

EXAMPLES

The antibody were obtained from rabbit hybridoma producing antibodiesthat block the interaction of VEGF with its receptor (VEGF-R2). Thehybridoma were generated by fusing immunized rabbit splenocytes with therabbit hybridoma fusion partner 240E-W2.

Rabbits were immunized with an Fc fusion protein. To express the fusionprotein, the human VEGF165 coding sequence was cloned into theC-terminal of rabbit IgG Fc which contains the signal peptide sequenceof rabbit IgG heavy chain at its N-terminus. The fusion protein wasproduced in HEK 293 cells and secreted into the culture medium. Toobtain the pure protein for immunization, the supernatant was harvestedand purified through a protein A column. The eluted protein was dialyzedagainst PBS buffer.

New Zealand white rabbits were immunized with the immunogen. Each rabbitreceived a primary immunization by subcutaneous injection of 0.4 mg ofthe purified protein with complete Freund's or TiterMax adjuvant. Theanimals were then boosted by subcutaneous injection of 0.2 mg of theprotein with incomplete Freund's or TiterMax once every three weeks. Thefinal boost (0.4 mg protein in saline) was given intravenously 4 daysbefore splenectomy.

Cell fusions were performed following the conventional protocol ofSpieker-Polet using PEG. The ratio of splenocytes to the fusion partnerwas 2:1. The fused cells were plated in 96-well plates and HAT was addedafter 48 hrs to select for hybridomas.

Direct ELISA was performed to identify antibodies that block binding ofVEGF to a VEGF-R2 fusion protein coated onto a microtiter plate.Antibodies identified in this assay were then were screened for blockingVEGF interaction with its receptor in a ligand-receptor assay. Theblocking antibodies were identified by their inhibition of binding ofFc-VEGF-R2 (Extracellular domain) or VEGF-Fc in solution to Fc-VEGF orFc-VEGF-R2 coated on plates.

cDNAs coding the heavy and light chains of the antibodies were clonedand sequenced.

1. A method of reducing binding of human VEGF to a human VEGFR2 (VEGFReceptor 2), comprising: contacting human VEGF with a monoclonalantibody that binds to said human VEGF and comprises: a) an antibodyvariable domain comprising: i. a heavy chain variable domain comprisinga CDR1 region identical to amino acid residues 30-35 of SEQ ID NO: 4, aCDR2 region identical to amino acid residues 50-66 of SEQ ID NO: 4 and aCDR3 region identical to amino acid residues 98-109 of SEQ ID NO: 4; andii. a light chain variable domain comprising a CDR1 region identical toamino acid residues 23-35 of SEQ ID NO: 43, a CDR2 region identical toamino acid residues 51-57 of SEQ ID NO: 43 and a CDR3 region identicalto amino acid residues 90-101 of SEQ ID NO: 43; or b) a variant of saidantibody variable domain that is otherwise identical to said antibodyvariable domain except for up to 8 amino acid substitutions in said CDRregions, wherein binding of the monoclonal antibody to said human VEGFreduces binding of said human VEGF to said VEGFR2 receptor.
 2. Themethod of claim 1, wherein said VEGFR2 is present on a cell in vitro. 3.The method of claim 1, wherein said VEGFR2 is isolated.
 4. The method ofclaim 1, wherein said VEGFR2 is present on a cell in vivo.
 5. The methodof claim 4, wherein said contacting is done by administering saidmonoclonal antibody to a human or mouse subject.
 6. The method of claim5, wherein said monoclonal antibody inhibits a VEGFR2-mediated activityof human VEGF in said subject.
 7. The method of claim 5, wherein saidsubject has a VEGF-related condition.
 8. The method of claim 5, whereinsaid monoclonal antibody is administered to said subject in apharmaceutically-acceptable carrier.
 9. The method of claim 1, whereinthe amino acid sequences of the framework regions of the heavy chain andthe light chain of said monoclonal antibody are different from theframework regions of SEQ ID NO: 4 and SEQ ID NO: 43, respectively, dueto humanization of said monoclonal antibody.
 10. The method of claim 1,wherein said monoclonal antibody comprises a human constant domain. 11.The method of claim 1, wherein said monoclonal antibody is a monovalentantibody.
 12. The method of claim 1, wherein said monoclonal antibody isa bivalent antibody.
 13. The method of claim 1, wherein said monoclonalantibody is a single chain antibody.
 14. The method of claim 1, whereinsaid monoclonal antibody is humanized.
 15. The method of claim 1,wherein said monoclonal antibody is a Fab, Fv, scFv, or Fd fragment. 16.The method of claim 1, wherein the monoclonal antibody comprises: a) anantibody variable domain comprising: i. a heavy chain variable domaincomprising a CDR1 region identical to amino acid residues 30-35 of SEQID NO: 4, a CDR2 region identical to amino acid residues 50-66 of SEQ IDNO: 4 and a CDR3 region identical to amino acid residues 98-109 of SEQID NO: 4; and ii. a light chain variable domain comprising a CDR1 regionidentical to amino acid residues 23-35 of SEQ ID NO: 43, a CDR2 regionidentical to amino acid residues 51-57 of SEQ ID NO: 43 and a CDR3region identical to amino acid residues 90-101 of SEQ ID NO: 43; or b) avariant of said antibody variable domain that is otherwise identical tosaid antibody variable domain except for up to 5 amino acidsubstitutions in said CDR regions.
 17. The method of claim 1, whereinsaid monoclonal antibody comprises a variable domain comprising: a) aheavy chain variable domain comprising a CDR1 region identical to aminoacid residues 30-35 of SEQ ID NO: 4, a CDR2 region identical to aminoacid residues 50-66 of SEQ ID NO: 4 and a CDR3 region identical to aminoacid residues 98-109 of SEQ ID NO: 4; and b) a light chain variabledomain comprising a CDR1 region identical to amino acid residues 23-35of SEQ ID NO: 43, a CDR2 region identical to amino acid residues 51-57of SEQ ID NO: 43 and a CDR3 region identical to amino acid residues90-101 of SEQ ID NO:
 43. 18. The method of claim 1, wherein saidmonoclonal antibody comprises: a variant of said variable domain of parta) that is otherwise identical to said variable domain of part a) exceptfor 1 to 4 amino acid substitutions in said CDR regions.
 19. The methodof claim 18, wherein said variant of said antibody variable domain isotherwise identical to said antibody variable domain except for a singleamino acid substitution in one of said CDR regions.